Wear a "puffer scarf" this winter.
It seems the fashion commentators really don't know what to call them......"quilted", "puffy" or "down filled"............ does it really matter?
Those that are filled with down are usually more expensive. Down is actually the fine feathers that many birds have under their outer feathers. The down feathers work as insulators. That is, because air is trapped in their loose airy structure and body heat is kept from escaping.
The down used in clothing usually comes from domestic geese. The down comes from geese which are killed for their meat. It is not a common practice to kill birds just to use their down. There is a process called live plucking which involves plucking the down from a live bird, but this is illegal in the United States and most European countries.
Answer: Most birds migrate to find food, not because they are cold !!